linux-kernel - [PATCH 3.2 15/59] cdc-acm: fix possible invalid access when processing notification

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 18 Aug 2017 14:13:13 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Oliver Neukum" <oneukum@...e.com>,
        "Tobias Herzog" <t-herzog@....de>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>
Subject: [PATCH 3.2 15/59] cdc-acm: fix possible invalid access when
 processing notification

3.2.92-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tobias Herzog <t-herzog@....de>

commit 1bb9914e1730417d530de9ed37e59efdc647146b upstream.

Notifications may only be 8 bytes long. Accessing the 9th and
10th byte of unimplemented/unknown notifications may be insecure.
Also check the length of known notifications before accessing anything
behind the 8th byte.

Signed-off-by: Tobias Herzog <t-herzog@....de>
Acked-by: Oliver Neukum <oneukum@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/usb/class/cdc-acm.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -293,6 +293,12 @@ static void acm_ctrl_irq(struct urb *urb
 		break;
 
 	case USB_CDC_NOTIFY_SERIAL_STATE:
+		if (le16_to_cpu(dr->wLength) != 2) {
+			dev_dbg(&acm->control->dev,
+				"%s - malformed serial state\n", __func__);
+			break;
+		}
+
 		tty = tty_port_tty_get(&acm->port);
 		newctrl = get_unaligned_le16(data);
 
@@ -323,11 +329,10 @@ static void acm_ctrl_irq(struct urb *urb
 
 	default:
 		dev_dbg(&acm->control->dev,
-			"%s - unknown notification %d received: index %d "
-			"len %d data0 %d data1 %d\n",
+			"%s - unknown notification %d received: index %d len %d\n",
 			__func__,
-			dr->bNotificationType, dr->wIndex,
-			dr->wLength, data[0], data[1]);
+			dr->bNotificationType, dr->wIndex, dr->wLength);
+
 		break;
 	}
 exit: